Petrography and Provenance of Laecanius Amphorae from Istria, Northern Adriatic Region, Croatia Maria A
Total Page:16
File Type:pdf, Size:1020Kb
Petrography and Provenance of Laecanius Amphorae from Istria, Northern Adriatic Region, Croatia Maria A. Mange1 and Tamás Bezeczky2 1Department of Geology, UC Davis, One Shields Avenue, Davis, CA 95616 2Institute for Studies of Ancient Culture, Austrian Academy of Sciences, Bäckerstrasse 13, PF 8 1010 Vienna, Austria Amphorae sherds from the Laecanius workshop of Roman Istria (10–5 B.C. and 78 A.D.), Croatia, were studied by integrating archaeological and geological techniques including fabric analysis, thin-section petrography, X-ray diffractometry (XRD), and heavy mineral analysis. The fabric of the sherds showed distinctive characteristics, permitting their classification and allocation into nine fabric groupss. Petrography revealed that quartz is the dominant clastic component, whereas carbonate is common as temper; XRD provided information on firing temperatures that ranged between 750 and 900°C. The sherds contain diverse heavy mineral suites with generally high epidote and garnet proportions; zircon is occasionally important. Garnet/epidote ratios and the presence of diagnostic species (pyroxene, hornblende) showed systematic variations that coincided with similar variations in fabric characteristics. Heavy mineral signatures of amphorae produced in other workshops proved essential in differentiating them from Laecanius sherds. A comparative heavy mineral analysis of terra rossa samples from the vicinity of the workshop indicated that terra rossa was the major source for the paste. Differences observed in the heavy mineral composition of the sherds and terra rossa were interpreted by the spatial heterogeneity of the latter and the mixing of the paste with sandy temper. Fresh Adriatic sponge spicules in the majority of Laecanius sherds and the temper-derived, generally immature heavy mineral assemblages suggest that sandy deposits from the Adriatic were used for the clastic temper. INTRODUCTION Archaeology and geology have long benefited from collaboration because archaeological raw materials are predominantly geological. Geological laboratory techniques are, therefore, important in the analysis of artifacts made of stone or clay, the principal inorganic raw material of ancient times. Pottery is one of the most abundant artifacts at any Roman-period archaeological site, and the study of amphorae occupies a distinguished place in Roman ceramics research. Amphorae were the large two-handled pottery containers of the Greek and Roman world, used for the storage and transportation of liquids, especially wine, olive oil, and other foodstuffs. We conducted an interdisciplinary study on Roman amphorae manufactured during the first century A.D. at a prominent workshop on the western coast of the Istrian Peninsula in the northern Adriatic region. The aims of this study were (a) to use heavy mineral analysis, thin-section petrography, and X-ray diffractometry (XRD) to complement archaeological methods in the characterization and grouping of the amphorae, and (b) to determine the provenance of the material used for the paste and temper. Knowledge of the source and composition of raw material can provide insight into ancient transport, trade routes, and manufacturing practices, and reveal improvements or decline in technology. Output variation is controlled principally by the strength of the economy; therefore, any new knowledge on the production, distribution, and dating of amphorae from any Roman period will advance understanding of contemporary economy. The prolonged existence of pottery workshops in Istria, supported by the high output of agricultural products, has long been the focus 1 of archaeological research (Manacorda, 1994; Mazzocchin and Pastore, 1996–1997; Bezeczky, 1998; Cipriano and Mazzocchin, 1998; Martin-Kilcher, 2000; Pesavento et al., 2000; Tassaux, 2001), and in our integrated study, we concentrate on a so-far unexplored field of ceramics research in Istria. Key words: Dressel 6B amphorae, fabric analysis, heavy mineral analysis, temper, provenance THE ISTRIAN PENINSULA, PHYSIOGRAPHY, AND GEOLOGY The Istrian Peninsula in westernmost Croatia occupies an area of 2.820 km2 (Figure 1, inset), rising from sea level to about 1400 m in the Cicarija Mountains to the northeast. The southwestern part of the Peninsula is a 300-m-high karst plateau with a typical karstic landscape, characterized by 5–10-m-deep dolines (sinkholes) and karren (limestone pavements). The soil here is the conspicuous terra rossa, a red clay to silty-clay soil widespread throughout the Mediterranean. Terra rossa is intimately linked to carbonate rocks and is thus typically associated with karstic features, filling in cracks and sinkholes (Durn et al., 1999; Miko et al., 1999). This area is commonly referred to as “Red Istria” because of the intense red color of the soil. The Trieste-Pazin belt in central and northwestern Istria, with its grayish marly or sandy soil, is called the “Gray Istria.” The Cicarija Mountains to the north, with their bare white cliffs (“White Istria”), form a prominent background to the whole region. The geology of the Istrian Peninsula is relatively simple (Figure 1). As part of the northwestern region of the Adriatic Carbonate Platform (Velic et al., 1995), it comprises three principal units: (a) the Upper Jurassic to Cretaceous carbonate plain of southern and western Istria, (b) Cretaceous-Paleogene carbonate-clastic sequences occupying the eastern and northeastern part of Istria, and (c) a Paleogene flysch basin in central Istria. Upper Pleistocene loess occurs only in the southern and northeastern regions (Durn et al., 1999). Historical Background After the end of the Roman Republic and the chaos of civil war from which Augustus emerged victoriously in 31 B.C., the Roman Empire entered into a phase of peace and security that spread throughout the Empire and influenced, for a long time, the life and economy of the provinces. Political stability created economic well-being with thriving trade and cultural vitality throughout the Mediterranean. In the late Republican period, 2 3 Figure 2. Historical map of Istria and detailed map of Brijuni and Fazana. new settlements were established on Istria and their development continued in the early phase of the Empire (Figure 2). Augustus showed a continued interest in the region since the beginning of the war against Iapodes (35–33 B.C.). Two friends of his inner circle, Statilius Taurus and Maecenas, also owned properties in Istria. The Istrian wine reached the emperor’s table. Pliny (NH 2.127; 16.60; 17.31) tells us that Empress Livia liked the wine produced in Pucinum, near Tergeste. In the Mediterranean climate, a thriving agriculture developed and produced large quantities of wine and olives. The ancient sources (Pliny the Elder NH 15.9) regarded Istrian olive oil as one of the best on the market. The Roman proprietors of the villas on the Peninsula cultivated, harvested, and processed the olives; they also had their own oil presses, storage cellars, and ceramic workshops. The amount of olive oil produced by the Istrian agricultural estates (villas) was sufficient to fulfill the need of all the northern Roman provinces (Raetia, Noricum, and Pannonia) and those in northern Italy for more than a century. Excavations in these regions have brought to light large quantities of amphorae, both in civil settlements and in mili- tary camps. The production of olive oil in Istria, from the end of the first century B.C. to the beginning of the second century A.D., is well documented. Towards the end of the reign of emperor Hadrian (A.D. 117–138), the Istrian olive oil suddenly disappeared from the market, and from that time, the villas satisfied only the local demand (Bezeczky, 1998). 4 The Istrian Villas From Pula to Tergeste, traces of several villas with olive-producing facilities (Matijasic, 1993) have been discovered (Figure 2). The owners of the properties were mainly senators and members of the Roman elite (Tassaux, 2001). One of the best-known owners was the Laecanius family. They owned a villa at Fazana, 9 km north of Pula, a well-known amphora workshop in Istria (Figure 2). Gnirs (1910) who also found the amphora kiln of the workshop, excavated the villa at the turn of the last century. Between 10–5 B.C. and 78 A.D., the amphorae produced in this workshop were shipped to northern Italy and provinces beyond the Alps. Amphorae from this workshop have been found in 53 ancient sites in Italy, Austria, Croatia, Slovenia, Switzerland, Hungary, and Yugoslavia (Mazzocchin and Pastore, 1996–1997; Bezeczky, 1998; Cipriano and Mazzocchin, 1998; Pesavento et al., 2000). The Villas and Workshops Besides the villa and workshop (figlina) in Fazana, the remains of three other villas were discovered on the Island of Brijuni where amphorae, marked with Laecanius stamps, were identified. No other owner’s stamps were found, so these villas were also interpreted as being the property of the Laecanius family (Bezeczky, 1998, Tassaux, 2001). The Val Catena villa in Brijuni (Verige Bay) was a luxurious maritime villa with elegant peristyles and colonnades, developed atria, bathrooms, and an industrial area. Gnirs found another villa rustica on Monte Collisi (Kolci hill), on the northwestern part of the island (Gnirs, 1908; Bezeczky, 1998). There is another villa in Dobrika Bay, in the western part of the Island of Brijuni (Girardi Jurkic, 1985; Matijasic, 1993; Bezeczky, 1998). This villa was surrounded by a late Roman/Byzantine fortress (Castrum). In the three villas, the storage capacity of the cellars was 10,000– 12,000 amphorae annually. The products of the figlina include amphorae, stoppers, dolia, tiles, clay lamps, spicae, and heating pipes. The Laecanius amphorae are regarded traditionally as belonging to the Dressel 6B type (Figure 3), which is a typical product of the Istrian peninsula (Baldacci, 1967–1968; Carré, 1985). This form is characteristic for all the Laecanian amphorae, although there may be some variations among the individual pieces. There are differences even among amphorae with the same stamp. The most important feature of the Dressel 6B amphora is the chalice-shaped rim, which meets the neck at a sharp angle.